Commercially available Ultra-WideBand (UWB) tags are designed to meet the common demands of environments such as hospitals, manufacturing and inventory tracking. One of the major requirements for operating in these environments is an extended operating life. Extended operating life requires a large battery size, thereby resulting in a larger overall size of the tracking tag. Further, the tracking tag is enclosed within a waterproof protective casing that has an access door to allow replacement of the battery. To ensure that the case is waterproof, the access door typically includes a seal. The device includes a battery holder that allows the battery to be replaced. All these features result in a relatively large tracking tag. Large tracking tags are a distraction to, and have an influence on, the object being tracked.
Installation, configuration, and calibration of an RF tag based object tracking system for use in a sports environment is a labor intensive and iterative process that requires expert knowledge. Receivers are first installed around a perimeter of the sports environment and each receiver is manually aimed, by eye, at a predetermined location within the sporting environment such that uniform coverage of a specific region of the sports environment (e.g., a portion of a playing surface) is achieved. An initial system performance evaluation is completed by recording and manually analyzing location data determined by the object tracking system for an RF tag placed on a technician as he/she walks a predetermined path within the sports environment. The predetermined path is designed to establish receiver coverage of the sports environment by the object tracking system. The RF tag is placed in such a way that it is free of obstruction by the technician's body (e.g., the tag is on top of a hat worn by the technician).
This recording and manual analysis process is iteratively repeated, typically using three different paths of increasing granularity. After analyzing the location data from a current path, the technician will either manually adjust one or both of pan and tilt of one or more receivers and repeat the current path, or continue the process by performing the next path.
This approach requires that the technician has a system expert's intimate knowledge of receiver characteristics and associated skill to extract information from the location data recorded for each test path. The expert knowledge required is at a very high premium and the application of the knowledge varies from technician to technician.
Thus, installation of an RF tag based object tracking system (a) requires highly specific expert knowledge, (b) is time intensive, (c) is a labor intensive incremental adjustment process, (d) may result in the RF tag based object tracking system operating at adequate but not optimal performance, and (e) result in inconsistent performance from installation to installation.
Any given sports environment easily includes hundreds of athletes and other objects that are tracked by an object tracking system, where each athlete and/or object is configured with at least one tracking tag that transmits a wireless signal (ping) that is located by the object tracking system. While such tracking systems may be optimized for the sports environment during installation, such systems do not automatically monitor and/or optimize their performance during operation.
Receivers of an RF tag based object tracking system are positioned around an area of interest such that each receiver covers a portion of the area of interest and in combination the receivers cover all of the area of interest. For a sports environment, the tracked area is for example a field of play and may include sideline areas.
During installation, each receiver is configured with a single, fixed, set of characteristics that are selected to enable the receiver to detect “pings” (i.e. low power signal transmissions) transmitted from one or more RF tags located within a defined portion of the area of interest that is assigned to that receiver based upon anticipated environmental conditions. For example, one receiver may be configured with a high gain antenna and matching analog conditioning circuitry that includes a six-point-five GHz band pass filter.
In practice, the sports environment is subjected to continual change, both environmental and situational. Environmental changes within the sports environment include the introduction of powerful electromagnetic signals (e.g. Wi-Fi or wireless broadcast camera signal). Since the RF tag based object tracking system is based upon the receivers detecting pings from the RF tags, changes in the spectral content of the sports environment are often catastrophic upon the system's ability to locate the RF tags.
Situational changes (e.g., movement of the RF tags within the sports environment) result in changes of RF tag density (i.e., the number of tags within a certain area), and thereby changes in the amount and/or frequency of pings received by each receiver of the object tracking system. The static configuration of each receiver is selected to also adequately cover anticipated situational changes. Although situational changes are not usually catastrophic to locating the RF tags, tuning the object tracking system to handle worst case tag/ping densities comes at the expense of system performance in other areas. These changing situations and environmental conditions are problematic because the receivers are statically configured for optimal performance under specific conditions.
Since each receiver configuration is static, the object tracking system cannot perform optimally for all environmental and situational conditions. The dynamically changing environmental and situational conditions places constantly changing demands on each receiver. These demands make it impossible to consistently achieve optimal performance of the object tracking system since it is statically configured to meet only certain of these environmental and situational conditions.
Exacerbating this problem, the likelihood of environmental and situational changes is greatest on “Game Day” when the integrity of the object tracking system is most crucial.
In an attempt to have the object tracking system operate reliably on “Game Day,” all environmental and situational conditions likely to exist on “Game Day” are anticipated and receivers of the object tracking system are configured in anticipation of these conditions. The specialized configuration (e.g., additional circuitry) required to operate effectively with the anticipated conditions often have negative effects under different conditions. Therefore, when the object tracking system is statically configured to meet all anticipated “worst case” conditions, the object tracking system invariably has inherently sub-optimal performance when these anticipated conditions are not prevailing.
Further, where “game day” conditions are not fully anticipated, a catastrophic failure to determine locations of the RF tags may still occur within the object tracking system when such unanticipated conditions occur. Such catastrophic failure typically terminates operation of the object tracking system and requires a team of technicians to visit the stadium to physically swap out the installed receivers for receivers configured to handle the unanticipated conditions—if identified. Such receiver replacement is costly and time consuming and addresses the current environmental condition. However, such receiver replacement does not take into account any future unanticipated conditions that the system will be ill-equipped to handle.